Degree Days - Watching, Waiting and Staying Warm

September 22, 2009

By Rich Pope, Department of Plant Pathology

A near-perfect week!  Sept.13 - 20 provided seasonally normal temperatures, bright sunshine and some light rain at week's end; all of which are favorable to Iowa's maturing crop. As of Sept. 21, the mid-range forecast is calling for night temperatures that should NOT approach killing temperatures. If this bears out, it will mean no early frost in 2009.   

Degree day accumulation map for September 20, 2009

Late-season foliar diseases, especially northern corn leaf blight of corn, flourished on susceptible hybrids, and has likely reduced yields some in spots.  Soybean aphids were still found in some fields close to senescing, and winged aphids and nymphs were eary to find in central Iowa on it's overwintering host, buckthorn.



Rich Pope is a program specialist with responsibilities with Integrated Pest Management. Pope can be contacted at or by calling (515) 294-5899.

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